(1) Field of the Invention
The present invention relates to an optical disc which stores information signals recorded and to a reproduction apparatus for reproducing such optical discs, more specifically to an optical disc which stores multimedia data including digital moving picture data, audio data, and sub-picture data and to an optical disc reproduction apparatus for reproducing such optical discs.
(2) Description of the Prior Art
Interactive software titles of various genres, such as aerobics, education and cooking, have been becoming increasingly noticeable of late in the market of music and movie software titles. Such interactive software titles include a plurality of branches during the reproduction of an optical disc, with the user being able to select the branch-to addresses. Interactive software titles with simple mechanisms have already been achieved for conventional video CD applications.
The first basic technique for the achievement of interactive software is distributed recording. This refers, for example, to the division of a one-hour-long movie into, say, one-minute-long or five-minute-long sections which are recorded, in separate areas on a spiral track, but not in a sequential order. The second basic technique is random accessing in which pieces of image information stored in separate areas are read in an arbitrary order using a plurality of sets of control information. Such sets of control information for random accessing each include a reading order of the pieces of image information and address information specifying areas on the spiral track in which the pieces of image information are recorded. Here, there can be as many sets of control information as there are reading orders, with the user being able to select a reading order from a menu displayed on the screen.
In this way, interactive software can provide several courses that can be selected by the user using menus.
The following is a description of an interactive aerobics software title. This aerobics interactive software title has a plurality of shots of an instructor doing different exercises, with several reproduction routes being recorded in the title. These reproduction routes correspond to courses such as "make your waist slim," "make your legs slim," and "Lose five kilos" which can be selected by the user according to his/her purpose. As one example, if the user selects the "make your legs slim" course, a series of shots including leg exercises, such as moving around with rhythmical steps, jumping, raising right leg high, and raising left leg high, are reproduced in succession.
If the user selects the "make your waist slim" course, a series of shots concerning waist exercises, such as twisting the waist to the right and left or bending over, are reproduced in succession.
A menu which is displayed using image data and which includes these course titles is displayed on the screen when the user loads the optical disc into the disc reproduction apparatus. Then, after the user has selected a desired course from the menu in accordance with his/her purpose, physical condition and quickness, the disc reproduction apparatus sequentially reads a plurality of shots in a reproduction route which corresponds to the selected course. The read shots are converted into image signals to be displayed on the screen. Here, by following the instructor's movements which are displayed on the screen, the user can enjoy a desired exercise program in the comfort of their own home. Should the user get bored with the selected program or wish to try something new, he/she can select another course and adjust its level to suit him/her.
This kind of interactive software title recorded on an optical disc is ideal for a housewife who is on a diet since she can select an exercise program according to her physical condition and purpose and can exercise in between her chores. Such interactive software titles are also beneficial for company employees since they can complete a short exercise program, such as before going to work, in order to compensate for their lack of exercise.
Here, although conventional interactive software titles include a plurality of courses, these courses use a same reproduction order every time. For this reason, users tend to get bored with the exercise programs provided by such titles. For the example of an aerobics software title, the user can soon master the movements repeated in the lesson, so that such software titles quickly become routine to users. Here, there have been suggestions to provide a random reproduction function to the disc reproduction apparatus so as to avoid this tendency for the reproduced content to become routine. Such a random reproduction function, which is a function for reproducing pieces of data recorded on a storage medium in a random order, is widely used in the reproduction of music software. However, it is not desirable to use this function for interactive software titles since the function regards every piece of data recorded on the optical disc as a potential reproduction object. This is to say, for the example of an interactive aerobics title, conventional random reproduction could have a menu, a shot of the instructor raising his/her leg, and a shot of the instructor shaking his/her arms displayed in that order, which would clearly make no sense to the user and would be of little value as exercise.
As can be clearly seen from the above example, for certain kinds of interactive title, the reproduction of pieces of data recorded on the optical disc at complete random destroys the logical structure of reproduction routes for each course. To avoid such disordered reproduction, a user programming function may be used. Here, a user programming function is a function which invites the user to set the reproduction order of the course by himself/herself. Here, the manual or jacket of the software title can assist the user in setting such a reproduction order, with most modern disc reproduction apparatuses being equipped with this function. However, the setting of such functions tend to be rather complicated, so that users, such as housewives or office workers, may not have enough time for setting reproduction orders by themselves. Such time-consuming procedures may end up only discouraging users from using such aerobics software titles.